1. Field of the Invention
This invention relates to locking means, and more particularly, to an improved locking device for a pair of panic doors.
2. Description of Related Art
A pair of panic doors are typically provided with a special type of locking device that includes an actuating bolt and a latching bolt and operates in such a manner that, when the door is closed, one of the two door panels will urge against the actuating bolt mounted on the other door panel which in turn actuates the latching bolt to be protruded out to a recessed portion in the doorframe or floor, whereby the paired panic doors are locked by the locking device. One type of this locking device is illustratively depicted in the following with reference to FIG. 1 through FIG. 4.
FIG. 1 is a schematic side view of a coxventional locking device for a pair of panic doors, which is disclosed in U.S. Pat. No. 5,527,074. As shown, the locking device 1' is mounted on one door panel of a pair of panic doors. The locking device 1' includes an actuating bolt 8'. In FIG. 1, the actuating bolt 8' is protruded out of the swinging stile 11' of the door panel. When the other door panel (not shown) of the paired panic doors is closed, it will run into the actuating bolt 8', thereby pushing the actuating bolt 8' to the inside of the locking device. This action then causes a curved pivotable member 9' to be pivotally turned about an pivotal axis 71' disposed in a mounting casing 7' for accommodating the actuating bolt 8' and curved pivotable member 9', as illustated in FIG. 2. In consequence, the curved pivotable member 9' urges against an L-shaped board 51' provided at the bottom of a movable tube 5', thereby pushing the movable tube 5' to move upwards, and consequently causing a slidable bar 6' to move upwards. The upward moving of the slidable bar 6' then causes a latching bolt 61' to be protruded out of the top plate 12' into a recess 130' formed in the doorframe 13', whereby the paired panic doors are locked to the doorframe 13'.
FIG. 3 is a schematic exploded perspective view of the actuating mechanism in the locking device of FIG. 1 (i.e., the combined structure of the actuating bolt 8' and the curved pivotable member 9'). As shown, the actuating bolt 8' is subgtantially triangular in shape having inclined surfaces with respect to its moving directon, and is integraly formed with a block having a crosswise guide slot 81' for accommodating the guide pegs 90' on the curved pivotable member 9' and a longitudianal slot 82' for accomodating the main body of the curved pivotable member 9' . When the paired panic doors are closed, it will urge against the inclined surface of the actuating bolt 8', thereby pushing the actuating bolt 8' inward, consenquently causing the curved pivotal member 9' to be turned about the pivotable axis 71', of a mountig 7' for accomodating the actuating bolt 8' and curved pivotable member 9' as shown in FIGS. 4A through 4C. FIG. 4A shows a top view of the actuating mechanism when the actuating bolt 8' is protruded out of the swinging stile 11'; and FIG. 4B shows a top view of the same except when the actuating bolt 8' is being pushed inward.
One drawback to the forgoing locking device, however, is that the actuating bolt 8' could be easily tilted, as illustrated in FIG. 4C, if the direction of the exerting force F is unaligned with the longitudianl axis of the actuating bolt 8', which would cause the actuating bolt 8' to be unsmoothly pushed into the casing of the locking device. One solution to this problem is to apply lubricant to the actuating bolt 8'. However, the provided effect would be unsatisfactory.
Still one drawback to the foregomg locking device is that the forming of the cross-wise slot 81' and the lorgtudinal slot 82' in the actuating bolt 8' is quite laborious and complex in machining, causing the manufacture cost to be undesirably high.